Clutch



Feb. V23, 1943. F. c. PEARsoN CLUTCH Filed June 8, 1940 3 Sheets-Sheet 1 Feb. 23,1943. F. c. PEARsoN 2,311,997

CLUTCHA Filed June a, 1940 s'sheets-sneet 2 I Bnnentor fmzzi C @sabian y (Ittornegs Feb. 23, 1943. l F. c. PEARsoN 2,311,997

CLUTCH Filed June 8, 1940 s sheets-Sheet s Snventor Patented Feb. 23, 1943 CLUTCH Frank C. Pearson, Flushing, Mich., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application June 8, 1940, Serial No.. 339,437

1 Claim.

'Ihis invention relates to a releasable clutch, such a clutch as is used to couple the engine shaft and the transmission shaft of a motor vehicle.

An object of the invention is to improve the means for positioning the pressure plate and for withdrawing it when the clutch is released.

It is also within the contemplation of the in- Ventor to use an externally located spring to effect clutch engagement.

Other objects and advantages will be understood from the description which follows.

In the drawings:

Figure 1 is a plan view, partly broken away and in section, of a part of a motor vehicle having my clutch embodied therein.

Figure 2 is a view in elevation of a part of the vehicle shown in Figure 1.

Figure 3 is a transverse section through the clutch.

Figure 4 is a View as seen from line 4-4 of Figure 3.

Figure 5 is a section substantially on line 5 5 I of Figure 4.

Figure 6 is a view like Figure 5 but with the parts displaced.

Referring to thel drawings, Figure 1 shows a vehicle frame II. The clutch between the engine and the transmission is enclosed within a housing marked I3. The engine shaft I5 (see Figure 3) carries, secured thereto at l1, a flywheel I9. A cover 2| has a radial flange secured to the flywheel at 23. The bottom oi the `cover is spaced from the flywheel and has a large opening leaving merely a radially extending ange 25. To this flange are secured adjustably a plurality of fulcrum studs 21 adapted to be engaged by levers 29, the latter beinlg pivoted at 3| to arms 33 of a pressure plate 35. A spring marked 31 is used to prevent rattling and to retain pivot 3| as shown. 'Ihe pressure plate may be provided with a centrally disposed disc 39 for the purpose of checking air flow through the clutch and to thereby prevent the passage of oil to the region of the clutch facings.

The driven shaft 4| is surrounded by a bearing sleeve 43. Surrounding the sleeve is an axially moving ball bearing 45. The ends 41 of a clutch lever 49 (see Figure 1) carry parts 5| which move the bearing through the instrumentality of an intermediate sleeve 53. 'I'he bearing engages the inner ends of levers 29. 'I'he clutch lever 49 is pivoted at 5| within the housing I3 and projects through an opening 55 in the housing.

The driven member of the clutch is carried by sha-ft 4| and is adapted to be gripped between the ywheel and pressure plate as is usual. This driven plate includes a hub 51 mounted to rotate with shaft 4| and an outer annulus 59 which carries the friction iacings 6|. If preferred, there may be used torque transmitting springs 63, as shown on the drawings, and operable between the hub and the annulus 59. As will be understood by reference to Figure 1, a counterclockwise rotation of clutch lever 49 moves bearing 45 toward the ywheel. 'Ihis movement of the bearing rocks levers 29 which fulcrum at 21, the pressure plate being moved thereby toward the flywheel to grip the driven plate.

To produce the above described rotation of clutch lever 49 the following construction is used. Journaled for rotation on the engine and clutch housing I3 as at 65 is one end of a rockshaft 61. The outer end of the rockshaft is journaled at 69 to a part II of the frame II. The engine end of the rockshaft 61 has an upwardly extending lever arm 1| and a downwardly directed arm 13. The gear box 15 which carries the gearing by which the steering shaft 11 operates, is secured by a bracket 19 to the frame I I. To the top of the gear box is secured a plate 3|. Between its front and rear ends this plate has an angular portion 83 apertured for the passage of an eye-bolt 85 held in position by a nut 81. To the eye of the eye-bolt is secured one end of a clutch engaging coil spring 89. The other end of the coil spring is attached to the lever arm 13. A compression rod or link 9| connects arm 1| with the end of clutch lever 49. It will be seen that spring 89 operates to rotate rockshaft 61 clockwise as seen in Figure 2, and that a counterclockwise rotation (Figure 1) is imparted to clutch lever 49. This pushes the bearing 45 to the left and the pressure'plate is moved by the levers 29 to grip the driven clutch member.

The pedal 93 is used to release the clutch. The pedal rotates about a shaft 95 carried by a conventional frame support. The pedal hub interlocks with the hub of a lever 91, the lever 91 being connected by alink 99 to an arm |0| extending upwardly from shaft 61 at a point adjacent the vehicle frame. The lever 91 may be formed with a depending part |03 carrying adjustably a threaded member |05 to engage a cross member .|01 of the frame and to thereby limit the return movement of the pedal. When the pedal is depressed it operates through link 99 to rotate the rockshaft 61 in a counterclockwise direction.

, and the pressure plate.

` the chordal and radial regions merge.

This operates to pull the lever 49 against the action of the clutch engaging spring and serves to release the clutch.

With this arrangement for clutch release, some means should be provided to move the pressure plate away from the flywheel when the clutch pedal overcomes the clutch engaging spring 89. Inthe present construction this means takes the form of a plurality of resilient flat plates, which plates have the added function of transmitting torque between the flywheel and cover assembly 'I'hey also have the further'function ofV centering the pressure plate. Because of this provision, any friction between the flywheel and cover assembly and the pressure plate is avoided. The expedient is best shown in Figure 4 where one of the resilient plates serving to center the pressure plate and to effect its release is marked |09. This spring plate is attached at about its middle point by fastening means III to a lug H3 of the pressure plate. The spring plate extends in both directions from H3 and forms what is substantially a chord of the circle of the clutch. The ends of the plate are bent away from the chordal direction Yand become more nearly radial. These ends are attached by fastening means I I5 to the under surface of flanges II'I formed on parts of the cover, which parts are spaced axially from the fiywheel and circumferentially from the cover fastening means 23. The plates |09 in their preferred form are normally bent or twisted when not loaded, the bend being preferably in the region where They are iiexed to a flat condition when the clutch is engaged. These two positions, engaged and disengaged, are shown by Figures 5 and 6. I-t will be understood that resilient energy is stored in the spring members |09 (of which there may be three as suggested by Figure 4) when the clutch is engaged, which energy is available to move the pressure plate away from the flywheel when the greater force of the clutch engaging spring 89 is overcome by the depression of the clutch pedal.

The avoidance of the sliding of the pressure plate in contact with the cover which is a commonly employed construction does away with friction and the centering of the pressure plate is assured. The construction provides a large central opening since the cover is not used as an abutment for the packing springs. The region of the cover periphery between its points of attachment to the ywheel is spaced axially from the flywheel. This is best shown by Figures 5 and 6, these figures indicating the cover outline. It shows the cover as extending downwardly (see dotted lines) to its points of attachment at 23 to the flywheel I9. The openings thus provided give a better air circulation than is usual and thus tend to avoid overheating of the friction facings.

I claim:

In a clutch for engine driven vehicles having a vehicle frame, an engine housing and a tf1-"airs versely disposed rockshaftv with its ends supported adjacent the vehicle frame and the engine housing,- said rockshaft having rst and' second oppositely directed arms, a single spring to effect clutch engagement said spring having one end xedly anchored and its other end attached to the rst of said arms, a clutch lever, a link connecting the second arm with the clutch lever, said rockshaft having a third arm extending in the same direction as the second arm, a manuf' ally operable lever and means connecting said manually operable lever and said third arm, said first and second arms being at the engine end of the rockshaft and thev third arm being atthe other end of the rockshaft.

FRANK C. PEARSON. 

